:root {
    --primary-color: #4285f4;
    --hover-color: #3367d6;
    --error-color: #dc3545;
    --success-color: #28a745;
    --background-color: #f5f7fa;
    --card-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
    --transition-speed: 0.3s;
    --sidebar-width: 250px;
}

.admin-container {
    min-height: 100vh;
    display: flex;
    background-color: var(--background-color);
    font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

.sidebar {
    width: var(--sidebar-width);
    background-color: var(--primary-color);
    color: white;
    padding: 1.5rem;
    position: fixed;
    height: 100vh;
    overflow-y: auto;
}

.sidebar-title {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    text-align: center;
    font-weight: 500;
}

.menu-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.menu-item {
    margin-bottom: 0.5rem;
}

.menu-link {
    display: block;
    padding: 0.75rem 1rem;
    color: white;
    text-decoration: none;
    border-radius: 6px;
    transition: background-color var(--transition-speed) ease;
}

.menu-link:hover,
.menu-link.active {
    background-color: var(--hover-color);
}

.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    padding: 2rem;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid #e0e0e0;
}

.header-title {
    color: var(--primary-color);
    font-size: 1.5rem;
    font-weight: 500;
    margin: 0;
}

.logout-button {
    padding: 0.5rem 1rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 0.875rem;
    text-decoration: none;
    transition: background-color var(--transition-speed) ease;
}

.logout-button:hover {
    background-color: var(--hover-color);
}

.form-container {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--card-shadow);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    color: #333;
    font-size: 0.875rem;
}

.form-input {
    width: 100%;
    padding: 0.85rem 1rem;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    font-size: 0.875rem;
    transition: all var(--transition-speed) ease;
    background-color: white;
}

.form-input:hover {
    border-color: #bdc3c7;
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(66, 133, 244, 0.2);
}

.form-button {
    width: 100%;
    padding: 0.85rem 1rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color var(--transition-speed) ease;
}

.form-button:hover {
    background-color: var(--hover-color);
}

.form-button:active {
    transform: scale(0.98);
}

.message {
    padding: 0.75rem;
    border-radius: 6px;
    margin-bottom: 1rem;
    font-size: 0.875rem;
    text-align: center;
    animation: slideIn 0.3s ease-out;
}

@keyframes slideIn {
    from {
        transform: translateY(-10px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.message.success {
    background-color: rgba(40, 167, 69, 0.1);
    color: var(--success-color);
    border: 1px solid rgba(40, 167, 69, 0.2);
}

.message.error {
    background-color: rgba(220, 53, 69, 0.1);
    color: var(--error-color);
    border: 1px solid rgba(220, 53, 69, 0.2);
}